The studies have identified a proteolytic procoagalant enzyme from malignant tissue that initiates clotting by directly activating factor X. Currently this procoagulant is being purified by standard purification methods including affinity chromatography. Substantial purification has been facilitated. Using the unique enzymatic properties of this procoagulant to measure and identify it, its levels in normal and malignant (and transformed) cells in culture will be measured to determine whether it is unique to the malignant state. Furthermore, its relation to tumor genesity and metastatic potential will be studied with selected cultured cell lines. BIBLIOGRAPHIC REFERENCES: Lewis, B.J. and S.C. Gordon: Cancer procoagulant A (CPA) activity in cultured normal and transformed fibroblasts. Federation Proc., 36, 1082 (1977). Gordon, S.G. and M. Overland: Analysis of abnormal protease activity in tissue culture medium from pseudoxanthoma elasticum (PXE) fibroblasts (Fbs). Clin. Res. 25:100A, 1977.